Package org.apache.kafka.streams

Class KeyQueryMetadata

java.lang.Object

org.apache.kafka.streams.KeyQueryMetadata

public class KeyQueryMetadata
extends Object

Represents all the metadata related to a key, where a particular key resides in a KafkaStreams application. It contains the active HostInfo and a set of standby HostInfos, denoting the instances where the key resides. It also contains the partition number where the key belongs, which could be useful when used in conjunction with other APIs. e.g: Relating with lags for that store partition. NOTE: This is a point in time view. It may change as rebalances happen.

Field Summary

Fields

Modifier and Type	Field	Description
static final KeyQueryMetadata	NOT_AVAILABLE	Sentinel to indicate that the KeyQueryMetadata is currently unavailable.

Constructor Summary

Constructors

Constructor	Description
KeyQueryMetadata(HostInfo activeHost, Set<HostInfo> standbyHosts, int partition)

Method Summary

Modifier and Type	Method	Description
HostInfo	activeHost()	Get the active Kafka Streams instance for given key.
boolean	equals(Object obj)
int	hashCode()
int	partition()	Get the store partition corresponding to the key.
Set<HostInfo>	standbyHosts()	Get the Kafka Streams instances that host the key as standbys.
String	toString()

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Field Details

NOT_AVAILABLE

public static final KeyQueryMetadata NOT_AVAILABLE

Sentinel to indicate that the KeyQueryMetadata is currently unavailable. This can occur during rebalance operations.

Constructor Details

KeyQueryMetadata

public KeyQueryMetadata(HostInfo activeHost,
 Set<HostInfo> standbyHosts,
 int partition)

Method Details

activeHost

public HostInfo activeHost()

Get the active Kafka Streams instance for given key.

Returns:

active instance's HostInfo

standbyHosts

public Set<HostInfo> standbyHosts()

Get the Kafka Streams instances that host the key as standbys.

Returns:

set of standby HostInfo or an empty set, if no standbys are configured

partition

public int partition()

Get the store partition corresponding to the key.

Returns:

store partition number

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object